This invention relates to the control of air flow and has particular reference to a valve that is mountable in a wall of a hydrotherapy spa or the like with an actuator that is accessible from the outer side of the wall and operable to control a flow of air from inside the wall to a hydrotherapy jet of the spa.
Control valves of this general type are known and used in hydrotherapy systems to control the amount of air that is introduced into a jet stream of fluid issuing from a jet into a spa, from no flow to a relatively high rate of flow. The air typically is drawn into the jet through a conduit that is open to the outside atmosphere, and the control valve is interposed in the conduit, between the jet and the atmosphere, to vary the effective flow area of the conduit and thereby vary the volume of air that is drawn into the jet stream.
An example of such a hydrotherapy system is shown in U.S. Pat. No. 4,592,100 wherein a control valve is recessed into the rim of a spa with a rotary control knob accessible from the outside and operable to move an inwardly extending valve member back and forth between open and closed positions. Air is drawn into the jet stream through the control valve from inside the wall, and a flexible check valve is provided to prevent back flow of fluid through the control valve.
This invention constitutes an improvement in this general type of control valve for performing the same basic functions but with a significantly different structure and improved operation.